I have my own TCP Server application listening on myIP and myPort, that shows everything that enters. It works well,(I tried sending data through Telnet) but don't enter anything from the TK102.Can anyone tell me whats wrong?

Who did you purchase the TK102 from? As far as I know it won't honour sms if its in gprs mode. I just got one last week and integrated into my gprs server to talk to my own software. I have not been able to configure to automatically send me data via gprs but everytime it sends me a heartebeat every minute. I ask for it a position and that seems to work.

Not sure if I will look too much into it as it only lasts 12-18 hours in GPRS mode.

Is it not sending any data to server? Maybe your GPRS is still off. Can you please confirm it by 'gprs123456' where 123456 is your password. After gprs ok message check status by check123456 and see whether GPRS is ON or OFF.